Device for covering shafts

ABSTRACT

The invention relates to a device for covering shafts of manholes in roads, comprising a tube ( 3 ) which is slideably guided in a covering ring ( 2 ) that is rigidly fixed on the shaft ( 1 ) proper, and a retaining ring ( 4 ) for receiving the shaft cover positioned in the plane of the road surface ( 6 ). Flexible fastening and simple construction is obtained by mounting the retaining ring ( 4 ) on the tube ( 3 ) so as to be detachable, with a limited degree of movement.

[0001] The invention relates to a device for covering shafts or manholesin roads, comprising a tube which is slideably held in a covering ringthat is rigidly fixed on the shaft proper, and a retaining ring mountedon the tube, that will receive the shaft cover positioned in the planeof the road surface.

[0002] Conventional shaft covers for sewers etc. essentially consist oftubular elements with a frame on top, which will support a cover. In thecase of rainwater drains the cover will have holes while in the case ofsewers a sealing cover will be provided. The lower end of the shaftusually rests on the sewer conduit generally extending in horizontaldirection. Due to temperature changes, especially freezing, and otherfactors in the road foundation horizontal and vertical movements willinevitably occur. Traffic on the road will also generate considerableloads. Conventional rigid shaft systems will not be able to follow thesemovements or will do so only to a limited, extent. This will lead todamaging of individual parts and to situations in which the shaft coveris no longer in the plane of the road surface, thus creating an obstacleand a source of danger for road traffic. Repair work and the exchange ofparts will be relatively cost-intensive.

[0003] From WO 82/04276 an arrangement for a shaft cover is known, inwhich a frame part for the cover is anchored in an upper layer of theroad foundation by means of a supporting element in the shape of aspherical cap. The under side of the frame part is provided with asleeve extending downwards and loosely enveloping the shaft tube, suchthat a certain degree of axial movement is possible. Changes in theheight of ground due to freezing may thus be at least partiallycompensated. However, if a shift in parallel with the road surface or aninclination occurs in addition to the changes in height, this cannot becompensated. Furthermore the tube may seize in the sleeve thus impedingthe desired function.

[0004] From the applicants of WO 99/53148 a pertinent device is knownwhich permits the adaptation of the shaft system to prevailingconditions, especially to the distance of the shaft proper from the roadsurface, by inserting intermediate rings. These individual rings maymove against each other to a limited degree, such that certain movementsof the road surface due to freezing etc. may be followed withoutdamaging any parts. The system will also permit tilting of the topmostring, which will be necessary when the road is inclined. Although thissystem perfectly fulfills all the requirements, it must be noted that itconsists of a multitude of parts and is therefore costly.

[0005] AT 403 492 B shows a shaft cover in which a cover frame is fixedto a tube which is sealingly connected to the sewer proper. In this wayit is possible to adapt the position and inclination of the framecarrying the cover to changes in the height of the road surface. Ifchanges in the road surface due to maintenance work or freezing etc.cause the inclination of the frame to change, this will lead to a shiftof the frame in the direction of the road surface, however, which shiftis impeded by the frame being firmly anchored in the road surface. Thiswill cause problems or breaking of the device.

[0006] It is the object of the present invention to avoid thesedisadvantages and to present a simplified solution having essentiallythe same functionality. In particular the system should be easy tomanufacture and apply.

[0007] According to the invention this object is achieved by mountingthe retaining ring on the tube in a detachable way and allowing it acertain degree of movement. The covering ring is rigidly attached to thetopmost shaft ring. This rigid attachment may be effected by screwing orsimilar means, but in many cases it will be sufficient to simply placethe covering ring on top of the shaft ring, since backfilling with earthor material of the road base will create sufficient pressure to keep itsecurely in place. Subsequently the tube is inserted into the coveringring, and thus into the interior of the shaft, as far as required. Sincethe retaining ring is movably attached on the tube, tilting movementsdue to inclination of the road surface may be compensated, thusincreasing the flexibility and safety of the system. The essential pointof the invention is that vertical adaptation can be achieved duringconstruction as well as during operation by a relative movement of thetube against the covering ring, and that tilting movements and smallvibrations due to traffic may be compensated by the flexible attachmentof the retaining ring on the tube. The device according to the inventionallows for independent changes both in height and inclination, bothduring work on the road, such as surface renewal, and in currentoperation when freezing or thermal expansion occurs.

[0008] It is of particular advantage if the retaining ring is tiltableagainst the tube, such that the axes of the retaining ring and the tubeenclose a small angle in the tilted position. In particular it isprovided that the angle between the axis of the retaining ring and theaxis of the tube should not be greater than 20°, and preferably not morethan 10°. In this way the usually occurring inclinations or tilts can besecurely compensated.

[0009] The shaft cover may reliably and permanently be kept in the planeof the road surface if the retaining ring is provided with a supportingface which is to be positioned on the road base. In addition, theretaining ring may be provided with anchoring elements for fixing it inthe road build-up.

[0010] A particularly advantageous variant of the invention providesthat the tube is furnished with a number of anchors which are attachedto the retaining ring in a manner permitting some play. It is ofadvantage if the anchor can be fastened or released by rotating theretaining ring relative to the tube. The fastening is thus effected by akind of modified bayonet catch.

[0011] The entry of undesirable external water may reliably be avoidedby furnishing the inner diameter of the covering ring with a seal actingagainst the outer periphery of the tube.

[0012] Installation of the device according to the invention isfacilitated by press fitting the covering ring on the tube. In this casethe covering ring is mounted on the tube prior to installation and iskept in place by the press fit. During assembly the end of the tube isinserted into the topmost shaft ring until the covering ring restsagainst the top face of the topmost shaft ring. The covering ring willthus keep the tube in place and will keep it from slipping down into theshaft ring. In this situation the surrounding region of the tube can befilled with material of the road base, securing the covering ring on theshaft and providing axial guidance for the tube. By applying sufficientforce to overcome the holding force of the covering ring and thesurrounding material the tube may be shifted downwards. After placementof the retaining ring the road surface may be built flush with the upperedge of the retaining ring. The procedure described is particularlysimple and not prone to failure. Preferably the covering ring and thetube are made of plastic material; choice of a suitable plastic materialfor the covering ring may eliminate the need for a separate seal againstthe tube and thus reduce cost.

[0013] In order to better guide the retaining ring on the tube and toenhance ease and safety of installation the retaining ring may beprovided with a collar enveloping the tube. In this way sand or dirt maybe prevented from penetrating between retaining ring and tube.

[0014] The invention will be explained in further detail below withreference to the following figures.

[0015]FIG. 1 is a lateral view of a device according to the invention inthe fully assembled state,

[0016]FIG. 2 is a sectional view along line II-II of FIG. 1,

[0017]FIG. 3 is a section as shown in FIG. 2 with the retaining ringtilted,

[0018]FIG. 4 is a view of the retaining ring from above,

[0019]FIG. 5 is a lateral view of the retaining ring,

[0020]FIG. 6 is a section along line VI-VI in FIG. 4,

[0021]FIG. 7 is a lateral view of the tube,

[0022]FIG. 8 is a lateral view of the tube in a further variant of theinvention.

[0023]FIG. 1 shows a shaft 1 carrying a device according to theinvention, which device includes a covering ring 2, a tube 3 and aretaining ring 4. The covering ring 2 is placed on the front face ofshaft 1 and fixed in position by material of the road base indicated by5. The retaining ring 4 is flush with road surface 6 and may receive ashaft cover not shown.

[0024]FIG. 2 shows a situation immediately after installation of thedevice and before backfilling with road base material. The tube 3 isheld by the covering ring 2 due to friction, and the retaining ring 4rests on the tube 3 and is in its lowest position. FIG. 3 shows theretaining ring 4 in a tilted position against tube 3 wherebyinclinations of the road surface 6 may be taken into account. Theretaining ring 4 may also be lifted as a whole relative to tube 3 inorder to have leeway in the building of the road surface 6. In theposition shown in FIG. 3 the axis 4 a of the retaining ring 4 enclosesan angle α of about 3° with the axis 3 a of the tube 3.

[0025]FIG. 4 shows the retaining ring 4 with a flange 7 whose undersideis provided with a surface 8 upon which the ring rests. From the flange7 a ring 9 extends upwards which is used to center a cover (not shown)or a cover frame and is supported by exterior ribs 10. The retainingring 4 is provided with cages 11 at regular intervals along a circle,each of which cages 11 has a slot 12 for fastening the tube 3. FIG. 7shows that the tube 3 carries anchors in the form of bolts 13 which areto be inserted in the slots 12. In this way the retaining ring 4 isfastened to the tube 3 with a limited degree of movability. In thevariant of FIG. 8 hooks 13 a are provided instead of the bolts 13, whichengage in recesses of the retaining ring 4 not shown in the drawing.This will prevent cages 11 from presenting an obstacle duringinstallation.

[0026] The covering ring 2 and the tube 3 are made from plastic, the fitat the site of contact 14 being a press fit, which means that the tube 3may be shifted against the covering ring 2 only by the application of aforce exceeding the total weight of the device. In this way it isguaranteed that the device is stable during installation.

[0027] The retaining ring 4 is further provided with a collar 15extending downwards from the bearing surface 8, which envelops the tube3 with some play thus guiding and centering the tube.

[0028] The present invention is particularly well suited for thecovering of sewer shafts in difficult situations, e.g. in roads withhigh traffic load, strong temperature fluctuations, etc. It is obviousthat the invention will not be limited to road-related applications butmay be of use also in other contexts.

1. Device for covering shafts or manholes in roads, comprising a tube 3which is slideably held in a covering ring 2 that is rigidly fixed onthe shaft 1 proper, and a retaining ring 4 mounted on the tube 1, thatwill receive the shaft cover positioned in the plane of the road surface6, characterized in that the retaining ring 4 is mounted on the tube 3so as to be detachable, with a limited degree of movement.
 2. Deviceaccording to claim 1, characterized in that the retaining ring 4 istiltable against the tube 3, such that the axes 3 a, 4 a of theretaining ring 4 and the tube 3 enclose a small angle α in the tiltedposition.
 3. Device according to claim 2, characterized in that theangle α between the axis 4 a of the retaining ring 4 and the axis 3 a ofthe tube 3 does not exceed 20°, and is not more than 1°, preferably. 4.Device according to any of claims 1 to 3, characterized in that theretaining ring 4 is provided with a supporting face 8 which is to bepositioned on the road base.
 5. Device according to any of claims 1 to4, characterized in that the retaining ring 4 is provided with anchoringelements for fixing it in the road build-up.
 6. Device according to anyof claims 1 to 5, characterized in that the tube 3 is furnished with anumber of anchors 13 which are attached to the retaining ring 4 in amanner permitting some play.
 7. Device according to claim 6,characterized in that the anchor 13 may be fastened or released byrotating the retaining ring 4 relative to the tube
 3. 8. Deviceaccording to any of claims 1 to 7, characterized in that the innerdiameter of the covering ring 2 is provided with a seal acting againstthe outer periphery of the tube
 3. 9. Device according to any of claims1 to 8, characterized in that the covering ring 2 is mounted on the tube3 by a press-fit.
 10. Device according to any of claims 1 to 9,characterized in that the covering ring 2 is made of plastic materialintegral with the tube
 3. 11. Device according to any of claims 1 to 10,characterized in that the tube 3 is made of plastic material.
 12. Deviceaccording to any of claims 1 to 11, characterized in that the retainingring 4 is provided with a collar 15 enveloping the tube 3.